Towing cable with fairings



y 3, 1965 D. A. NICHOLS ETAL 3,

TOWING CABLE WITH FAIRINGS 2 s heets -sheet 1 Filed Feb. 1, 1965 AT'IURNEY y 3, 1965 D. A. NICHOLS ETAL 3, 9

TOWING CABLE WITH FAIRINGS Filed Feb. 1, 1963 2 Sheets-Sheet 2 INVENTORSI pom/140 4. Mars 04s F055;??- [1/ ns-4 c:

ATTORNEY.

United States Patent 3,194,204 TUWING CABLE WITH FAIRENGS Donald A. Nichols, Niantic, and Robert W. Pierce, New

London, Conn, assignors to the United States of America as represented by the Secretary of the Navy Filed Feb. 1, 1963, Ser. No. 256,205 14 Claims. (Cl. 114-435) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to towing cables with fairings thereon, which are used .to tow a submerged object from a ship, and which when not in use is wound on the periphery of a large drum on the rear of a deck of the towing ship.

Many naval ships make considerable use of cables to tow submerged objects through which signals and vibrat-ions may be sent and/or received In time of military activities, such ships often must move at high speeds because of the possible presence of enemy craft or when engaged in battle. When ordinary cylindrical cables are used to tow a submerged object at high speeds, the water resistance or drag on such cables is large, and the lower end of such a cable tends to trail far behind the towing ship. The trailing cable tends to rise toward the sea surface, and the force required to tow it becomes very large. At high speeds it has been difiicult to keep the towed, submerged object at the desired depth below the sea surface. If the length of the cable is increased to obtain the desired depth of the towed object at high speeds, such a length of cable makes it unwieldly, and increased force is required to tow it.

Such towing cables have been supplied with fairings thereon to reduce the water resistance or drag on the cables, to reduce the force required to tow .it at high speeds, and to enable successful use of shorter lengths of cables.

An object of this invention is to provide an improved cylindrical towing cable with fairings thereon, which will keep the fairings in approximate alignment along the length of the towing cable, which will have minimum possible drag in the water, which has greater strength and durability in use than prior fairings, which may be towed in water at high speeds with a minimum of power expenditure, which enables variations to be made in the buoyant effect of each fairing, which enables replacement of any damaged fairing in a simple manner without removal of other fairings, which may be wound on drums for storage when not in use, and when so wound the fairings remain approximately in abutting end to end relation to one another along the cable, and which will be relatively simple, strong, durable, effective in reduction of drag, and inexpensive.

Other objects and advantages will appear from the following description of one embodiment of the invention, and the novel features will be particularly pointed out in connection with the appended claims.

In the accompanying drawings:

FIG. 1 is a schematic illustration of how a towing cable with fairings thereon may be used;

FIG. 2 is a plan, partly in section, of a portion of a towing cable, with two fairings or fairing units thereon and constructed in accordance with this invention;

FIG. 3 is a front elevation thereof; and

FIG. 4 is a perspective of a portion of a towing cable and a fairing unit thereon which has been constructed in accordance with this invention.

The fairing units embodying this invention are formed of an elongated nose piece of channel shape in the open longitudinal face of the channel of which one edge or side portion of a tail piece of buoyant material is detachably secured, leaving a space or passage between the bottom of the channel and the received edge or side of the tail piece through which the towing cable extends and on which the fairing unit is pivoted, and the fairings are detachably coupled end to end in a manner to permit limited flexing of the towing cable as the cable with fairings thereon is towed, or is wound on a drum for storage when not in use.

In the illustrated embodiment of the invention, and referring first to FIG. 1, a flexible towing cable 1 is secured at one end to and wound upon a drum 2 that is rotatably mounted upon the deck of a ship 3, adjacent the rear end of the ship. Suitable means, notshown, is provided upon the ship for rotating the drum to wind the towing cable thereon for storage when it is not in use, or to control rotation of the drum in the opposite direction when paying out the cable for use, The means for rotating the drum to wind the cable thereon, and to control rotation of the drum in paying out the cable for use is well known, and hence, the details thereof are not illustrated or further described.

The towing cable 1 at its free end is attached in the usual manner to an object 4 which is to be towed submerged, and such an object may be a device which is used .to send or receive signals and vibrations that are transmitted through the water. this object are not mateiial to this invention, except that a bundle of conductors 5 (FIG. 4) may be enclosed in the cable and protected by a spiral winding 6 of metal wires that abut side by side and form a protecting shell for the conductors 5 and through which the towing force is conveyed to the object 4.

A plurality of fairings or fairing units 7 are pivotally secured upon the towing cable 1 end to end from adjacent the object 4 to that part of the cable 1 which is above the water line while the object 4 is being towed, as shown in FIG. 1. One of such fairing units 7 is shown in perspective in FIG. 4 as applied to the tow cable 1. Two of such fairing units 7 are shown as connected to one another and to the towing cable 1 in FIGS. 2 and 3. Each fairing or unit is formed of a nose piece 8 that is of elongated channel shape, and a detachable tail piece 9 that is formed of a material which is floatable in water, i.e. is buoyant in water. The nose piece is of strong sheet material and preferably at present is made of sheet metal forced by dies in a press into U-shaped in cross section, with the bottom of the U approximately semi-circular and forming the bottom of the channel. The width of the channel, which corresponds to the distance between the arms of the U is preferably slightly larger than the diameter of the towing cable 1 so that the fairing unit 7 may pivot or swivel about the cable 1.

The tail piece 9 has a side edge portion 10 which is received between the arms of the U of the nose piece, to fill and close the open face of the channel, but leaving between it and the bottom of the channel a space serving as a passage through which the cable 1 passes. The side faces of that part It) of each tail piece which are received between the arms of the U, i.e., within the channel, are notched slightly at 11 to receive the arms of the nose piece flush or countersunk in the tail piece, so that the outer side faces of the nose piece and tail piece will be continuously flush where they meet and overlap.

The bottom wall of the channel or U is arcuate and concave on its outer face from end to end, as at 12, so that The particular details of ends 13 of each nose piece are somewhat convergent, so that adjacent ends of adjacent nose pieces will be divergent from one another. This permits the fairing units to remain in contact at their nose pieces as the towing cable 1 flexes in use (see FIG. 1) or as wound on the drum. A plurality, such as three for example, of fastener or coupling elements 14 have their heads countersunk in the side arms of the nose piece and extend between and connect those side arms, and also extend through the marginal or side portion of the tail piece which is received in the channel, so as to lock the tail piece detachably in the channel of the nose piece. Each coupling element 14 is preferably formed of a tubular member 15 which extends through the tail piece from face to face and has a passage therethrough lengthwise from end to end, which passage is threaded at each end and preferably from end to end. Screws 16 are threaded into both ends of this passage and have their heads countersunk into depressions in the nose piece, which depressions of the nose piece are in turn countersunk into depressions or recesses in the opposite faces of the tail piece. The portions of the nose pieces which are countersunk into the faces of the tail piece act as keys to prevent relative sliding movement between the nose and tail pieces, in addition to the tubular members 15 which serve that purpose also. By removing the screws 16 from the ends of each tubular member 15, the nose and tail pieces may be separated for replacement of a new nose and/ or tail piece.

Each tail piece in the marginal portion received in the nose piece, at each end has a notch 17 which opens through the adjacent end face of the tail piece and also through the side edge face that is within the channel and faces the bottom of the channel. Each such notch 17 extends somewhat beyond the coupling element 14 which is nearest that end of the tail piece. surrounds the elements 14 near adjacent ends of the tail pieces, and serves to connect together adjacent ends of adjacent fairing units. The loops of the links 18 are longer than the distance between the endmost couplings 14 of adjacent fairing units, so that the connected fairing units may have some lost motion between them, enabling limited separation of adjacent fairing units where connected by the links, which is necessary to allow the towing cable to flex or take an arcuate form (see FIG. 1) in use, or when wound on the drum 2 for storage when not in use. In other words, the coupling 14 may move in the loops of the links to a limited extent when the tail pieces separate, as will be obvious from FIGS. 2 and 3.

Each tail piece adjacent to but spaced from its trailing edge 19, is provided with a pair of recesses 29 and 21 at different distances from the trailing edge 19, with the recesses 20 aligned lengthwise with one another in adjacent tail pieces, and the recesses 21 similarly aligned lengthwise with one another. Each recess 26 and 21 opens through both end faces of the tail piece, but the opening through one of such end faces is restricted as at 22 for the recesses 20, and at 23 for the recesses 21. The tail pieces are arranged end to end with the recesses 20 of one pair opening fully to one another, and the recesses 21 of each tail piece of this pair opening fully to one another with the other tail pieces adjacent thereto, as shown in FIG. 2.

A flexible element 24 is disposed in both aligned recesses 26 of one pair which open fully toward one another, so as to couple together the trailing parts of the adjacent tail pieces. This allows the tail pieces to separate somewhat near their trailing edges, yet remain coupled by the flexible elements as the tow cable is flexed, and thus be kept in approximately side by side alignment during the flexing of the cable. A flexible element in the two aligned recesses 21 that open fully toward one another serves to similarly flexibly connect together each of the tail pieces shown in FIGS. 2 and 3. Thus, each tail piece is connected at one of its ends by a rod or element 24 to the adjacent end of the adjacent tail piece, and

A closed loop link 18 at its other end by a flexible rod or element 25 to the adjacent end of the other adjacent tail piece.

It is possible by providing other recesses or cavities selectively placed in each tail piece to vary the relative positions of the center of buoyancy and center of weight of the tail piece, and thus, vary the buoyancy of the tail piece and create a tendency for the tail piece to move upwardly or downwardly on the cable where the cable with fairings thereon is submerged in water.

Examples of the flexible elements or rods 24 and 25 are lengths of rubber hose, or lengths of an acetyl resin such as is marketed by the Du Pont Co. under the trademark Delrin. The molecular structure of the polymer is that or" a linear acetyl consisting of unbranched polyoxymethylene, and it has a chain of great length, normally averaging more than 1000 (EH 0 units, with a specific gravity of about 1.425 Preferably, each of the rods and 25 is a length of rubber hose with a flexible rod within and extending along the passage of the hose. The acetyl resin useful as a flexible rod such as rods 24 and 25, used alone or within the rubber hose, was described in Product Engineering of September 29, 1958 on pages 36-41.

The nose and tail pieces are substantially stream-lined from the nose piece rearwardly to the trailing edge 19 of the tail piece, which reduces the drag of the water on the cable and hence, reduces the power or force required to tow it in the water, particularly at high speeds. The tail pieces are preferably made of polypropylene resin which enables the tail pieces to be molded, and this material is very buoyant in water and strong and durable in use.

Each complete fairing section including its nose and tail pieces, links 118, members 15, screws 16 and rods 24 and 25, will sink if released in the sea or ocean, and hence, will slide down the tow cable. The bottom fairing unit rests upon an end piece 26 (FIG. 1) to which it is coupled by a link 18 and a rod 24, and this piece 26 is pivoted to the object 4 being towed.

The fairing, composed of many sections or units, prevents vibration of the tow cable as the towed body is towed at various speeds. As a result, there are no nodes in the cable which might cause the armor wires 6 to be broken by fatigue.

It will be understood that various changes in the details, materials, and arrangements of parts, which have been herein described and illustrated to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

We claim:

1. A sectional fairing unit for tow cables which coinprises:

(a) a tail piece of a material floatable in water,

(b) a nose piece of channel shape having the leading edge of said tail piece received in its channel and leaving a passage in the channel between the tail piece and nose piece through which a tow cable may pass and by which the tail piece is pivotally confined to the tow cable,

(c) coupling means passing between the side walls of the nose piece and through the part of said tail piece received in said nose piece for detachably confining said tail piece to said nose piece, and

(d) a closed link confined to one end of the tail piece by said coupling means and extending endwise from the tail piece for loose coupling to an adjacent tail piece.

2. A fairing for a tow cable, comprising (a) a plurality of fairing units for pivotal mounting end to end on said cable along its length,

(b) each such unit having a tail piece of buoyant material, and a nose piece detachably secured to an edge of the tail piece and forming with that edge a passage through which said tow cable may be passed in succession and on which the uni-ts may swivel,

(c) each such unit being streamlined from its nose piece toward the trailing edge ofthe tail piece, and

(d) the leading margin of each nose piece being concavely arcuate from end to end to conform to the approximate peripheral curvature ofa drum on which the tow cable with fairing is expected to be wound when not in use, and also having its ends outwardly convergent from the tail piece to provide clearance between ends of adjacent units when the tow cable with units thereon is wound on said drum.

3. The fairing according to claim 2, and flexible means coupling adjacent ends of adjacent units for limiting pivotal movement of any unit on the tow cable relatively to adjacent units.

4. A tow cable with fairings thereon by which a submerged object may be towed from a ship, which comprises:

(a) a flexible tow cable,

(b) a plurality of fairing units arranged in end to end relationship along, and individually pivotally mounted along one side edge on said cable,

(c) each such unit having a tail piece of buoyant material connected along an edge to a channel-shaped nose piece, with the'cable received in the channel of the nose piece to extend lengthwise therein and confined by the nose piece to said one edge of the nose piece,

(d) the ends of adjacent nose pieces being divergent outwardly past the cable from the tail pieces to which they are attached to facilitate rocking of the nose pieces of adjacent units on one another as the cable with attached fairings is wound on the periphery of a drum for storage when not in use for towing.

5. A tow cable with fairings thereon by which a submerged object may be towed from a ship, which comprises:

(a) a flexible tow cable,

(b) a plurality of fainng units arranged in abutting,

end to end relationship along, and individually pivotally mounted along one side edge on said cable,

(c) each such unit having a tail piece of buoyant material connected along an edge to a channel-shaped nose piece, with the cable received in the channel of the nose piece to extend lengthwise therein and confined by the nose piece to said one edge of the nose p1ece,

(d) the free edge of the nose piece along which said cable extends being concave in a direction lengthwise of the nose piece with a curvature approximately conforming to the curvature of the periphery of a drum on which the towing cable, with fairings thereon, is expected to be wound when stored and not in use for towing purposes.

6. A tow cable with fairings thereon by which a submerged object may be towed from a ship, which comprises:

(a) a flexible two cable,

(b) a plurality of fairing units arranged in end to end relation along and individually pivotally mounted along one side edge on said cable,

(c) each such unit having a tail piece of a material floatable in water, and a channel shaped nose piece, in the open face of which channel a side of said tail piece is detachably received, with a space in the bottom of such channel receiving said cable lengthwise therein to provide a pivotal connection of each tail piece to said cable,

(d) each tail piece having a notch in each end thereof in the portion of the tail piece which is received in said channel and opening outwardly through the adjacent end and also through the side face that is received in said channel of said nose piece, and

(e) fastening elements, passing through said notches of each tail piece and also the part of said nose piece which receives said tail piece to couple together said nose and tail pieces of each unit,

(f) a link disposed in the notches of adjacent ends of adjacent tail. pieces, held therein by said fastening means that passes through the notches and flexibly connecting together adjacent units with some lost motion providing for limited separation of adjacent units as said cable flexes,

(g) said unit being generally streamlined in shape from the nose piece rearwardly to the trailing edge of said tail piece.

7. A tow cable with fairings thereon by which a submerged object may be towed from a ship which comprises:

(a) a flexible tow cable,

(b) a plurality of fairing units arranged in end to end abutting relationship along, individuallyfi pivotally mounted along one side on said cable, and streamlined from its leading edge to its trailing edge,

(c) each such unit having a channel-shaped sheet metal nose piece with its bottom wall arcuately concave on its outer surface, and a tail piece of polypropylene having an edge portion received in the open longitudinal face of the channel of said nose piece but leaving a space along the bottom of the channel through which said cable extends,

(d) the arms of said nose piece being set flush in the face, surfaces of the tail piece that are received in the channel,

(e) coupling means for each unit passing through said nose piece and the part of the tail piece received therein for detachably coupling the nose and tail pieces, and

(f) means detachably connecting adjacent units with sufiicient lost motion to enable limited separation of the units as the cable with fairing is wound on a drum,

(g) whereby any fairing may be removed for replacement by manipulating said coupling means to uncouple the nose and tail piece thereof and enable separation of the said uncoupled pieces from one another and removal from the cable.

8. The cable with fairings thereon according to claim 7, wherein said coupling means includes a plurality of elements each having endwise separable, telescoping members insertable from opposite faces of said nose piece, and said detachable connecting means includes links received loosely in the ends of each tail piece and surrounding said elements of adjacent units near the adjacent ends of the adjacent units.

9. The cable with fairings thereon according to claim 7, wherein the bottom of the channel of each nose piece is curved lengthwise to fit approximately the periphery of a drum on which the cable with fairlings thereon may be wound for storage.

10. The cable with fairings thereon according to claim 7 wherein the ends of the nose pieces of adjacent fairings are divergent in a direction away from the tail pieces thereof, to enable flexing of the cable without material endwise separation of the nose pieces of adjacent units as the cable with fairings thereon is wound on the periphery of a drum for storage.

11. The cable with fairings thereon according to claim 7 wherein (a) the bottom of the channel of each nose piece is curved lengthwise to fit approximately the periphery of a drum on which the cable with fairings thereon may be wound for storage, and

(b) wherein the ends of the nose pieces of adjacent fairings are divergent in a direction away from the tail pieces thereof, to enable flexing of the cable without material endwise separation of the nose pieces of adjacent units as the cable with fairings 27 thereon is wound on the periphery of a drum for storage.

12. The tow cable with fairings thereon according to claim 1 wherein the tail piece is of polypropylene.

13. A sectional fairing unit for tow cables which comprises:

(a) a tail piece of a material fioatable in water,

(b) a nose piece of channel shape having the leading edge of said tail piece received in its channel and leaving a passage in the channel between the tail piece and nose piece through which a tow cable may pass and by which the tail piece is pivotally confined to the tow cable,

(0) coupling means passing between the side walls of the nose piece and through the part of said tail piece received in said nose piece for detachably confining said tail piece to said nose piece, and

(d) a closed loop link confined to one end of the tail piece by said coupling means and extending endwise from the tail piece for loose coupling to an adjacent tail piece, said tail piece having (e) two passages from end face to end face at different distances from said nose piece, and

(f) a flexible rod contained in one of said two passages and extending endwise from the tail piece for insertion into the corresponding passage of the tail piece of an adjacent tail piece to couple adjacent tail pieces and cause them to swivel together on said tow cable.

14. A tow cable with fairings thereon by which a submerged object may be towed from a ship which comprises:

(a) a flexible tow cable,

(b) a plurality of fairing units arranged in end to end 8 relation along, and individually pivotally mounted along one side edge on said cable,

(c) each such unit having a channel-shaped nose piece and a tail piece of a material floatable in water received within the open face of the channel of the nose piece and leaving between it and the bottom of the channel a space approximately fitting and receiving the said tow cable, and

(d) flexible means for separately and loosely coupling each tail piece to its adjacent tail piece adjacent the trailing edges of the tail pieces, and for keeping adjacent fairings all generally aligned along the tow cable,

(e) said flexible coupling means including two parallel recesses in the end faces of each tail piece at diflerent distances between the nose piece and trailing edge of the tail piece, with a loose flexible rod disposed in the aligned recesses of adjacent faces of each fairing tail piece with the adjacent fairing tail piece at one side, and another loose flexible rod disposed in the other aligned recesses of the other adjacent faces of the other adjacent fairing tail piece.

References Cited by the Examiner UNITED STATES PATENTS 2,401,783 6/46 Wilcoxon 114-235.2 2,891,501 6/59 Rather 114-2352 FOREIGN PATENTS 108,761 8/ 17 Great Britain.

251,893 2/27 Italy.

FERGUS S. MIDDLETON, Primary Examiner.

MILTON BUCHLER, Examiner. 

1. A SECTIONAL FAIRING UNIT FOR TOW CABLES WHICH COMPRISES: (A) A TAIL PIECE OF A MATERIAL FLOATABLE IN WATER, (B) A NOSE PIECE OF CHANNEL SHAPE HAVING THE LEADING EDGE OF SAID TAIL PIECE RECEIVED IN TIS CHANNEL AND LEAVING A PASSAGE IN THE CHANNEL BETWEEN THE TAIL PIECE AND NOSE PIECE THROUGH WHICH A TOW CABLE MAY PASS AND BY WHICH THE TAIL PIECE IS PIVOTALLY CONFINED TO THE TOW CABLE, 